Rinsing Activated carbon with RODI

C. Eymann

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Yes it is standard practice to remove dust/fines but I remember reading a long time ago in a book that rinsing/soaking carbon in RO/DI not only removes dust and possible PO4 but also helps open up the pores and essentially increases its performance VS not rinsing/soaking at all or rinsing/soaking with freshly made salt water.


Sound feasible? or hogwash? and why?
 
I rinse my gfo and carbon when I do a water change. I leave extra saltwater in the sump after the water change. As in a level above my normal running line and then turn on the manifold to rinse it into a bucket. I probably run a gallon or so through it until it runs clean plus whatever extra to get my sump to the correct level.

I never heard before what you are talking about and is possible news to me. Both products are cheap enough where I would not even worry about it. I will take the lazy way out to make my routine more efficient.
 
I rinse my gfo and carbon when I do a water change. I leave extra saltwater in the sump after the water change. As in a level above my normal running line and then turn on the manifold to rinse it into a bucket. I probably run a gallon or so through it until it runs clean plus whatever extra to get my sump to the correct level.

I never heard before what you are talking about and is possible news to me. Both products are cheap enough where I would not even worry about it. I will take the lazy way out to make my routine more efficient.

I wish I could remember the book, maybe it was Calfos book of propagation or Nielsen's and Fossa series.
It had an explanation that had something to do with the soft low pH nature of RODI helping open up the pores and giving the carbon some polarity.

I was hoping @Randy Holmes-Farley could explain and clear it up.
 
Well RO water is acidic right? Could this slightly acidic rinse clear out the pores in some fashion? So the ash is removed in a more efficient manner and naturally PO4 will leach out quickly/more efficiently when it is RO compared to salt water?
 
Well RO water is acidic right? Could this slightly acidic rinse clear out the pores in some fashion? So the ash is removed in a more efficient manner and naturally PO4 will leach out quickly/more efficiently when it is RO compared to salt water?

Thats why I have always rinsed mine in RODI, because my understanding is that the acidic nature of RODI will help open up pores better and may help increase the carbons polarity/absorption properties, surely its only minuscule I imagine.

However, is the science /chemistry behind those statements sound?
 
Yes it is standard practice to remove dust/fines but I remember reading a long time ago in a book that rinsing/soaking carbon in RO/DI not only removes dust and possible PO4 but also helps open up the pores and essentially increases its performance VS not rinsing/soaking at all or rinsing/soaking with freshly made salt water.


Sound feasible? or hogwash? and why?
Zeovit carbon recommends letting it stand in RODI, initially heated to around 90 C, for 24 hours.
 
I don't think it matters with Carbon as it is thought now that it only lasts about 3 days or so. BRS mentioned that in one of their videos and I read it somewhere else too.
 
Yes it is standard practice to remove dust/fines but I remember reading a long time ago in a book that rinsing/soaking carbon in RO/DI not only removes dust and possible PO4 but also helps open up the pores and essentially increases its performance VS not rinsing/soaking at all or rinsing/soaking with freshly made salt water.


Sound feasible? or hogwash? and why?

I don't believe the pore idea has merit. Removing fines is good. A little phosphate bound is a wasted effort.
 
Tap, rinse until clear, no issues.

But now I’m curious if it would be even better with Rodi, hmmmm.
 
I am with randy on this one. I don’t see how rinsing in Rodi is going to make it much better than rinsing in two water which most already do. The point is to get the fines out. I just use rox and so a quick rinse and that’s it.
 
Yes it is standard practice to remove dust/fines but I remember reading a long time ago in a book that rinsing/soaking carbon in RO/DI not only removes dust and possible PO4 but also helps open up the pores and essentially increases its performance VS not rinsing/soaking at all or rinsing/soaking with freshly made salt water.


Sound feasible? or hogwash? and why?

There is merit in the idea, but like many plausible sounding ideas, there is zero information about the magnitude of the effect, i.e., the claims are possibly true but the effects are so small that the benefits of extensive RO/DI rinsing make it a waste of time.

Why don’t you test the idea? It would be simple and inexpensive. If you need a few ideas on experimental design, let me know.
 
I always rinse with RO because I don’t want my new carbon sucking up chlorine, chloramines and other contaminants from my tap water.
Carbon removes organics /metals via adsorption, but these elements in town water supplies are negligible, so that's not a consideration when rinsing.

Carbon acts differently for chlorine, it does not adsorb it like metals or organics, rather it converts its form as it passes through - electron exchange, and carbons ability to do this is infinite.
Even when it has been depleted of its adsorption capacity, activated carbon still functions as an electron exchange medium for chlorine, meaning it will convert chlorine to chlorides. The exceptions being when there is channelling or total blinding of the carbon where direct contact with the carbon and chlorine is prevented.
So tap water is fine for rinsing.
 
Carbon removes organics /metals via adsorption, but these elements in town water supplies are negligible, so that's not a consideration when rinsing.

Carbon acts differently for chlorine, it does not adsorb it like metals or organics, rather it converts its form as it passes through - electron exchange, and carbons ability to do this is infinite.
Even when it has been depleted of its adsorption capacity, activated carbon still functions as an electron exchange medium for chlorine, meaning it will convert chlorine to chlorides. The exceptions being when there is channelling or total blinding of the carbon where direct contact with the carbon and chlorine is prevented.
So tap water is fine for rinsing.

Interesting.. that’s what I love about this hobby, learn something new every day :) I had always assumed carbon was actually absorbing chlorine & chloramines because my carbon blocks become less effective over time at removing them.

Of course everyones tap water is different but mine is particularly nasty with a typical TDS over 350, It will literally burn your eyes, leaves brown residue on everything and stinks if left standing a few days :( so I feel better rinsing my carbon in RO, I only use very small quantities of ROX-8 at a time so the rinsing is really quick and easy with very little dust.
 

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